ERV + dehumidifier ducting in a minisplit house
I’m working on a 2400sf house (CZ4, but very nearly 3) where the owners have selected minisplits – one ductless 1st floor, one ducted w/ very short runs for each of 2nd & 3rd. So there will be no major duct lines throughout the house for heatning and AC. They’ve also chosen to go the ERV and Dehumidifier route, this being the humid southeast.
I’m having trouble getting a straight answer from anyone about how to duct these two units without a central system to tie into. Some say keep each separate with it’s own set of 4″ smooth wall flex and distribution boxes, others say combining them and essentially running the units in parallel on the same set of ductwork. My concern with the combined system is that the Dehumidifier is ~200+ CFM and the ERV will be around a quarter of that. Separate systems seems like a lot of very small ducts.